CM3-Home

1-Wire interface

1-Wire is a device communications bus system designed by Dallas Semiconductor Corp. This article explains how to use it on the CM3-HOME-B and CM3-HOME-F boards

What is a 1-wire bus ?

The most popular use of 1-wire bus is to use the Dallas DS18B20 temperature sensors. The image below illustrates how to wire it on the screw terminals available on the CM3-Home board. It is possible to wire more than one sensor.

As depicted on the CM3-HOME schematic, the 1-wire data line is interfaced through a dedicated buffer in order to allow a more robust bus, therefore it doesn't require a pullup.

Configuration

To use the 1-wire sensor port add this lines to config.txt file and reboot:

# Enable the 1-wire bus 
dtoverlay=w1-gpio,gpiopin=16

The sensor wired are automatically detected by the Linux Kernel and a new directory is created on the folder /sys/bus/w1/devices for each of them.

$ ls /sys/bus/w1/devices/
28-000006c423d3

In this case a temperature sensor with id=28-000006c423d3 has been detected. To read the temperature value type:

$ cat /sys/bus/w1/devices/28-000006c423d3/w1_slave 
a4 01 4b 46 7f ff 0c 10 da : crc=da YES
a4 01 4b 46 7f ff 0c 10 da t=26250

eShop

EUR 290.00


CM3-HOME-F - CM3-Home board full (mother board only)

CM3-Home is a Raspberry Pi Compute Module 3 motherboard designed to provide a reliable Home Automation hardware equipped with a wide range of electrical interfaces

  • NOT INCLUDED:
    • Raspberry Compute Module 3 or 3L (Product # CM3L)
    • Yarm antenna (Product # YARM-ANT-01)
    • Case (Product # CM3-HOME-CASE)
    • MicroSD (Product # MICROSD8G-E)
  • Included:
    • WiFi module (Product # WIFI-2)
    • WiFi antenna (Product # AN-WIFI-01)

For more info please visit the product description page

| Product description || CM3-Home catalog |

Sergio Tanzilli
System designer, software developer and company co-founder
tanzilli@acmesystems.it
Webpages: https://www.acmesystems.it and http://www.tanzolab.it
Github repository: https://github.com/tanzilli and https://github.com/acmesystems